256721351892 has 96 divisors (see below), whose sum is σ = 637421460480. Its totient is φ = 80274447360.

The previous prime is 256721351891. The next prime is 256721351911. The reversal of 256721351892 is 298153127652.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256721351891) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3667848 + ... + 3737184.

It is an arithmetic number, because the mean of its divisors is an integer number (6639806880).

Almost surely, 2^256721351892 is an apocalyptic number.

It is an amenable number.

256721351892 is an abundant number, since it is smaller than the sum of its proper divisors (380700108588).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256721351892 is a wasteful number, since it uses less digits than its factorization.

256721351892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69681 (or 69679 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 51.

The spelling of 256721351892 in words is "two hundred fifty-six billion, seven hundred twenty-one million, three hundred fifty-one thousand, eight hundred ninety-two".